Denver Water Department Research Articles

XERISCAPING: A GREENING APPROACH FOR FACING WATER-SCARCITY IN ARID CITIES The case of Egypt

There is no doubt that green spaces provide the urban environments with an important asset, however the water-scarcity issues that is facing many urban settlements, Egypt is one of these places that is not only suffering from the rareness of green spaces, but the water scarcity issues as well, these issues have arose to the surface in the last several years forced the municipality's supply of these green spaces to decline dramatically. Xeriscaping is one of the methods that is used to challenge such scarcity, it is a method of gardening that doesn’t sacrifice beauty to conserve water, Xeriscaping (zer-i-scaping) is a water conservation technique that first originated in 1981 by the Denver water department. It is a 7 step landscaping method which aims at using drought-tolerant plants among a series of other steps to protect the environment. Water scarcity is a spreading phenomenon that affects all sectors of the community and threatens the sustainability of the resources. The “Water consumption versus water scarcity” reality in Egypt emphasizes the importance of following procedures for water conservation, and this could be tackled through a water-wise practice such as “Xeriscaping”. This paper summarizes the significance of Xeriscaping, its major characteristics; it aims at forming a framework which could be considered a counter measurement technique to mitigate the water scarcity phenomenon which is crippling the Egyptian economy.

Outsourced training helps utility fill code compliance need

The Denver Water Department (DWD) needed to prepare employees to pass the National Electrical Code (NEC) exams. This article describes how the utility created a quick and inexpensive training program that would not interfere with the section's operating functions.

Denver potable water reuse demonstration project: Comprehensive chronic rat study

The health effects testing program for the Denver Water Department's Potable Water Reuse Demonstration Project was designed to evaluate the relative health effects of highly treated reclaimed water derived from secondary wastewater in comparison with Denver's present high-quality drinking water. The 1 × 10 6 gal/day treatment plant provided 500-fold concentrates of water that had been treated by multiple processes to remove microbial and chemical contaminants. Fischer 344 rats were exposed to the complex mixture solutions for up to 2 yr to evaluate chronic toxicity and oncogenicity effects. The following parameters were evaluated: clinical observations, survival rate, growth, food and water consumption, haematology, clinical chemistry, urinalysis, organ weights, gross autopsy and histopathological examination of all lesions, major tissues and organs. Clinical pathology, gross pathology, and microscopic pathology conducted at wk 26 and 65 and at the end of the study did not reveal any findings that could be considered to be treatment related. Administration of drinking water concentrates at up to 500 times the original concentration in the original water samples to F344 rats for up to 104 wk did not result in any overt toxicological or carcinogenic effects.

Water District Maintains Dominion Over Groundwater

The Willows Water District (WWD) served 4,800 single‐family‐equivalent water taps. WWD was entirely within the Little Dry Creek watershed, a tributary to the South Platte River. WWD had two sources of water: nontributary groundwater (WWD water) and interruptable contract deliveries from the Denver Water Department. An engineering analysis authorized by WWD showed that 10 percent of irrigation water in the district accrued to the creek. Thus, WWD proposed to drill three wells in the tributary alluvium of the creek to pump groundwater in amounts equal to reusable return flows attributable to WWD irrigation water to fully augment any depletions to the creek and river. The Public Service Company of Colorado (PSC) objected to the plan. The application was approved, and the PSC appealed.

Primacy Funding Strategies

This Roundtable discussion took place June 20, 1992, in Vancouver, B.C. Pane1 moderator was Jack Hoffbuhr, deputy director of AWWA, 6666 West Quincy Ave., Denver, CO 80235. Other participants were B. David Clark, director of the Drinking Water Division, Washington Department of Health, P.O. Box 47822, Olympia, WA 98504‐7822; Steve Schmidt, vice‐president of American Commonwealth Management Services Co., P.O. Box 460, Hershey, PA 17033, and chairman of the Guidance Committee to Small Water Systems for AWWA; John Stubbart, president of Waimea Water Services Inc. and chairman of the Hawaii Section's Small Water System Committee, P.O. Box 326, Kamuela, HI 96743; and Rocky Wiley, manager of general planning, Denver Water Department, 1600 West 12th Ave., Denver, CO 80254, and director of the Rocky Mountain Section.

Conservation: An Expanding View

This Roundtable discussion took place June 24, 1991, at AWWA's annual conference in Philadelphia, Pa. Panel moderator was Rick Harmon, AWWA management development programs manager. Other participants were Bruce Adams, water conservation coordinator of the South Florida Water Management District, 3301 Gun Club Rd., West Palm Beach, FL 33416; George Raftelis, partner and director of national consulting practice, Ernst & Young, 1500 Independence Center, Charlotte, NC 28246; David M. Reeser, manager of environmental process engineering, Rust International Corp., P.O. Box 25374, Portland, OR 97225; Amy Vickers, consulting engineer, Amy Vickers & Associates, 100 Boylston St., Suite 702, Boston, MA 02116; and Steve Work, deputy director of water production, Denver Water Department, 1600 W. 12th Ave., Denver, CO 80254.

Wetlands

This discussion took place in Washington, D.C., July 19, 1990. The moderator was Robert H. Reinert, vice‐president, Malcolm Pirnie, 100 Eisenhower Dr., Paramus, NJ07652. Members of the panel were: Hope Babcock, general counsel, National Audubon Society, 801 Pennsylvania Ave. S.E., Suite 301, Washington, DC 20003; William B. Ellis, principal, vice‐president, and director, McSweeney, Burtch & Crump, 11 S. 12th St., Richmond. VA 23219; Robert E. Hall, intergovernmental affairs coordinator‐federal, Denver Water Department, 1600 W. 12th Ave., Denver, CO 80220; Wendell R. Inhoffer, general superintendent and chief engineer, Passaic Valley Water Commission, 1525 Main Ave., Clifton, NJ 07011; Kirk Stark, environmental scientist, elevated cases team, US Environmental Protection Agency, 401 M St. S. W., Washington, DC 20406; and John F. Studt, chief, regulatory branch, US Army Corps of Engineers, 20 Massachusetts Ave. N.W., Washington, DC 20314‐1000.

Comprehensive health effects testing program for Denver's potable water reuse demonstration project

The Comprehensive Health Effects Testing Program for the Denver Water Department's Potable Water Reuse Demonstration Project is designed to evaluate the relative health effects of highly treated reclaimed water derived from secondary wastewater compared to Denver's present high-quality drinking water. The 1 million gallon per day (1 mgd) demonstration plant provides water to be evaluated in the studies treating unchlorinated secondary treated wastewater with the following additional processes: high pH lime clarification, recarbonation, filtration, ultraviolet irradiation, activated carbon adsorption, reverse osmosis, air stripping, ozonation, and chloramination. An additional sample is obtained from the identical treatment process substituting ultrafiltration for reverse osmosis. The toxicology tests to evaluate the possible long-term health effects are chronic toxicity and oncogenicity studies in Fischer 344 rats and B6C3F1 mice and reproductive/teratology in Sprague-Dawley rats. The results of these evaluations will be correlated with microbiological, chemical, and physical test results to establish the relative quality of reclaimed water compared to all established health standards as well as Denver's pristine drinking water.

AWWA Two Forks Testimony Questioned

The December 1989 JOURNAL noted that AWWA testified in the public hearing on the Denver Water Department's controversial Two Forks Reservoir proposal which has been vetoed by the USEPA. While Mr. Carney is in agreement with the USEPA action, he is concerned that AWWA member opinion was not solicited before the organization testified. Mr. Carney agrees with the policy that AWWA rarely takes positions on local water issues. AWWA's testimony, in Mr. Carney's opinion, created the public perception that AWWA is a pro‐development, self‐serving advocate of water projects (at the expense of the environment, if necessary) instead of an objective, professional organization.

Managing Water to Promote Conservation

This discussion took place during the annual conference in Denver on June 23, 1986. Participants were Robert F. Banker, partner in the consulting firm of Black & Veatch, Kansas City, Mo.; Duane L. Georgeson, manager of the water system of the Los Angeles Department of Water and Power; and Donald L. Schlenger, director of development and research at the Hackensack Water Company, Hackensack, N.J., and vice‐president for corporate development of United Water Resources, the corporate parent of the Hackensack Water Company. William H. Miller, manager of the Denver Water Department, was moderator.

The Fair Labor Standards Act and the 12‐Hour Shift

This article discusses the impact of the Fair Labor Standards Act on the Denver Water Department, where treatment plant operators have been working on a 12‐hour shift schedule since 1980. A recent ruling on the Act does not outlaw the use of extended shifts, but it requires that all hours worked over 40 in a work week must be paid at the time and one‐half overtime rate. The Denver Water Department found that it could minimize overtime by redefining the work week so that operators' work hours were more evenly distributed between weeks. The new schedule produces a maximum of eight hours of overtime pay per operator every four weeks. A table illustrating Denver's 12‐hour shift schedule is presented.

Face to Face – Denver's Reuse Demonstration Plant: Forerunner of the Future?

William H. Miller, manager of the Denver (Colo.) Water Department, discussed treatment of wastewater effluent for direct potable reuse with Ida M. Sayre, associate editor of the Journal. Denver's reuse demonstration plant, now in operation, is intended to advance knowledge about the techniques needed to protect the public health as well as to evaluate the economics and feasibility of direct reuse. This interview took place May 15, 1985, in the Denver Water Department's administrative headquarters.

Roundtable – Drinking Water Research: How Are We Doing?

Priorities and goals of water industry research in North America were discussed during the 1984 annual conference in Dallas on June 11. Participants were: Wolfgang Kühn of the Engler‐Bunte Institute, Karlsruhe, Federal Republic of West Germany; Michael J. McGuire, water quality manager with The Metropolitan Water District of Southern California; William H. Miller, manager of the Denver Water Department; and J. Edward Singley, vice‐president of J.M. Montgomery Engineers, Gainseville, Fla. John B. Mannion, director of development and communications for the AWWA Research Foundation, was moderator of the roundtable.

Roundtable – Is Vandalism a Threat to Water Utilities?

This discussion about deliberate acts of vandalism aimed at water utilities took place during the 1983 annual conference in Las Vegas. Fred Elwell, chairman of the AWWA Water Utility Council and chief engineer of the Manchester Water Works. 281 Lincoln St., Manchester. NH 03103. was moderator. Other participants were Joseph A. Cotruvo, director of the Criteria and Standards Division. Office of Drinking Water, USEPA. Washington. DC 20460; William A. Kelley, chief of the Water Supply Division, Michigan Department of Health. 3500 N. Logan St., Lansing. MI 48914; James V. La Frankie, president of the American Water Works Service Co., 525 Grove St., Hadden Heights. NJ08035; and William H. Miller, manager of the Denver Water Department, 1600 W. 12th Ave., Denver, CO 80254.

Denver's water conservation program

The most obvious means of conserving water throughout the Denver Water Department's service area is to curb the thirst of homeowners' bluegrass lawns, which consume 80 percent of the residential water used during the summer months. In response to water shortages and a court decree, the water department has undertaken a variety of programs to restrict water use during the growing season and to develop a conservation ethic among customers without imposing unreasonable lifestyle changes.

Roundtable – Water conservation—the nemesis of water utility revenue

This discussion on the pros and cons of water conservation took place at the AWWA annual conference in Miami Beach on May 19, 1982. Jerome B. Gilbert, general manager of the East Bay Municipal Utility District (Calif.), was the moderator. Other participants were: Charles B. Carroll Jr., deputy utilities director of the city of Aurora, Colo.; Duane L. Georgeson, assistant manager of the Los Angeles Department of Water and Power; Wendell R. Inhoffer, general superintendent and chief engineer at the Passaic Valley Water Commission (N.J.); William O. Maddaus, project manager, Brown and Caldwell, Walnut Creek, Calif.; and William A. Tolle, deputy manager of the Denver Water Department.

Creating the Denver Water Department's security program

The Denver Water Department became aware of its security risks in 1975. Since then, a comprehensive risk management program has evolved that covers all of the department's security exposures ranging from its remote reservoirs to its urban administrative headquarters. An unexpected cost benefit was reduced insurance premiums.

Tracking Energy Usage

This article describes the Denver Water Department's approach to energy conservation in its operations. Its supervisory control system is capable of monitoring 470 points of information, such as pressure, flow, reservoir elevation, and valve positions. The Department's contract with the Public Service Company of Colorado, which facilitates peak shaving and load shifting, is described.

Computer Modeling Programs: Tools for Model Operations

Engineers and planners need a system of computer programs to effectively analyze water distribution systems. The days of using a single computer program to solve for pressure and flow variables have passed. Capabilities such as extracting and combining networks and allocating loads are a must for optimal system operation. Manipulation, comparison, and checking programs provide efficient and accurate methods to process data and determine trends and solutions. The Denver Water Department successfully uses one such system to operate efficiently and control costs.

Good‐by to the Graveyard Shift With the 12‐hour Shift Schedule

There are many benefits associated with 12‐hour shifts, rather than the traditional 8‐hour shift. Among operators surveyed by the Denver Water Department, the new schedule has created new possibilities such as less turnover, more consistency in operations, higher efficiency because operators stay to master their tasks, savings in energy, and new incentives for employees in the form of longer weekends every other week.